Astros take a flier on former All-Star pitcher Duke

The risk is low, which may or may not correspond with the potential rewards the Astros can reap by signing former All-Star pitcher Zach Duke to a minor-league contract.

Astros general manager Jeff Luhnow announced on Friday the signing of Duke, a native Texan who also received an invitation to spring training.

Duke, 28, is a lefthanded starter who has fallen on hard times since finishing fifth in the 2005 National League Rookie of the Year voting (8-2, 1.81 ERA in 14 starts for the Pittsburgh Pirates). A Clifton native and Fort Worth resident, Duke is 40-72 with a 4.81 ERA and .311 batting average allowed in the past six seasons.

With a fastball in the 87-mph range, Duke relies heavily on his changeup, curveball and control. He has walked only 2.4 batters per nine innings during his career but has a penchant for pitching to too much contact.

Duke has struck out 11.8 percent of the batters he has faced — well below the major-league average of 17.6 — in 1,041 innings. The Pirates traded Duke to the Arizona Diamondbacks after the 2010 season, but the change of scenery didn’t stop his strikeout rate from plummeting to 3.8 per nine innings (barely half the National League average of 7.3). Duke struck out 6.2 batters per nine innings during his rookie partial season of glory but has averaged only 4.5 since.

He spent his first six seasons in the majors with the Pirates, managing to make the All-Star team in 2009 despite leading the NL in losses (16) and posting a 4.06 ERA. Traded for a player to be named later (pitcher Cesar Valdez) in November 2010, Duke went 3-4 with a 4.93 ERA in 21 appearances (nine starts) last season for the NL West champion Diamondbacks.